System and method to protect privacy of personal-identification-number entry on consumer mobile device and computing apparatus

ABSTRACT

A system for accepting the input of a PIN comprises a first device receiving a randomized PIN layout derived on a fourth device. The randomized PIN layout is displayed on a display of the first device. A second device comprises an input for accepting a series of key presses to produce a PIN token. The PIN token indicating each of the series of key presses. A third device is in communication with the second device. The third device derives the randomized PIN layout and receives the PIN token from the second device without the PIN token being present on the first device. The third device combines the PIN layout and the PIN token to produce a PIN. The PIN is used to authenticate a transaction. The fourth and third devices each store a shared secret used to independently derive the randomized PIN layout on the fourth and third devices.

TECHNICAL FIELD

The present invention relates to a system and a method for secure PINentry on devices with insufficient security level such as mobilecomputing devices.

BACKGROUND

Electronic payments, transfers, and banking can be made by a variety ofmeans. Commonly, transactions require the use of a payment card or abank card, or a virtual card on mobile device. The user, card holder, oraccount holder typically interfaces the payment card with a paymentterminal or ATM machine. The most common form of security is a PIN(Personal Identification Number). A PIN is a short, numerical oralpha-numerical string and is input by a user as a security measure toverify their identity. The input is usually entered on a mechanical ortouchscreen keypad or keyboard on the payment terminal. Payments cardmay interface with the card reader interfaces of the payment terminalusing magnetic strips, direct electrical contacts, and through the useof short range wireless protocols such as RFID and NFC.

A typical payment terminal comprises of an interface for PIN entry, oneor more card reader interfaces for interfacing with cards, acommunication interface for communicating with the financial institutionthat processes the transaction, and payment applications to handle thetransaction flow and handle the human interaction with the transactionflow, and user interfaces such as a screen, keypad, or touch panel forproviding the means for user interaction. The high cost of paymentterminal prevents small merchants to accept card payments.

More recently, smart phones and tablets have become very common, andmost of the functionality in a traditional payment terminal can berealized on a smart device. The payment applications can be run on smartdevices, and the smart devices provides various communication methods toconnect with transaction processing entities. In such cases, thefunction of a payment terminal can be reduced to two essentialfunctions: accepting PINs and interfacing with cards. In mostapplications, the PIN is accepted on the payment terminal instead of themobile device, as it is difficult to ensure the privacy of a PIN on amobile device which was not designed for that purpose.

By utilizing mobile devices the cost of payment terminals is reduced, inparticular for card transactions which do not require a PIN, a simplecard reader can be used with smart devices to process card transactions.However, for transactions required PINs, the cost of PIN-acceptingpayment terminals is still too high for smaller merchants.

In order to increase the security of PIN entry using common consumermobile devices a number of improvements have been proposed. Many ofthese improvements are related to protecting the PIN and the encryptionkeys. One proposed improvement has been to use a random keypad thatchanges each time a PIN is input. A further improvement is to have twodevices, a first device to display the PIN layout and a second device toenter the PIN on. The PIN layout may be fixed, it does not change, orrandom, it changes each time a user is required to enter a PIN. Thesecond device for entering data may display only boxes or may display ablank screen. The user observes the first device to determine the layoutof the keys and inputs the PIN on the second device by pressing ortouching keys. the user input on the second device is transmit to thefirst device and the first device obtain the PIN. The first device canthen encrypt the PIN and send to the payment network. One drawback ofthese methods is that the PIN layout and PIN keystrokes, also referredto as a PIN token, are present on the same device and present a singlepoint of attack.

There exists a need for a PIN security solution where the PIN layout,PIN token do not exist together on the same device. Furthermore, it isadvantageous that any encryption keys also do not exist on the samedevice as the PIN layout or PIN token.

SUMMARY

A first major embodiment of the invention is a system for accepting theinput of a PIN comprising a first device receiving a randomized PINlayout from a fourth device. The fourth device derives the randomizedPIN layout and the first device displays the randomized PIN layout on afirst display of the first device. A second device comprises an inputfor accepting a series of key presses to produce a PIN token indicatingeach of the series of key presses. A third device is in communicationwith the second device. The third device derives the randomized PINlayout and receives the PIN token from the second device without the PINtoken being present on the first device. The third device combines thePIN layout and the PIN token to produce a PIN used to authenticate atransaction.

In some embodiments of the inventions the fourth device is incommunication with the third device with the fourth device and the thirddevice each storing a shared secret. The shared secret is used toindependently derive the randomized PIN layout on the fourth device andthe third device.

In other embodiments of the invention the third device is locatedremotely from the first and second device.

In further embodiments, the first device and the second device comprisea transaction authentication system and the transaction is used toauthenticate the veracity of a point of sale terminal. In otherembodiments, the transaction authentication system is used to acceptpayments from a customer payment device.

In some embodiments, the first device and the fourth device are the samedevice.

A second major embodiment of the invention is system for accepting theinput of a PIN. The system comprises a first device receiving arandomized PIN layout from a fourth device. The fourth device derivesthe randomized PIN layout. The first device displays the randomized PINlayout on a first display of the first device. A second device comprisesan input for accepting a series of key presses to produce a PIN token.The PIN token indicates each of the series of key presses. A thirddevice is in communication with the second device and the fourth device.The third device receives the randomized PIN layout from the fourthdevice and receives the PIN token from the second device without the PINtoken being present on the first device. The third device combines thePIN layout and the PIN token to produce a PIN that is used toauthenticate a transaction.

A third major embodiment of the invention is a system for accepting theinput of a PIN. The system comprises a first device receiving arandomized PIN layout from a third device that derives the randomizedPIN layout. The first device displays the randomized PIN layout on afirst display of the first device. A second device comprises an inputfor accepting a series of key presses to produce a PIN token thatindicates each of the series of key presses. The third device is incommunication with the second device and the fourth device. The thirddevice receives the PIN token from the second device without the PINtoken being present on the first device. The third device combines thePIN layout and the PIN token to produce a PIN that is used toauthenticate a transaction.

A fourth major embodiment of the invention is a method forauthenticating a purchase on a point of sale terminal. The methodcomprises displaying a randomized PIN layout on a first device. Thefirst device receives the randomized PIN layout from a fourth device.The fourth device derives the randomized PIN layout. The first devicedisplays the randomized PIN layout on a first display of the firstdevice. A PIN token is entered on a second device. The second devicecomprises an input for accepting a series of key presses to produce thePIN token. The PIN token indicates each of the series of key presses. Athird device receives the PIN token from the second device. The PINtoken is never present on the first device. The third device derives therandomized PIN layout and combines the PIN layout and the PIN token toproduce a PIN. The PIN is used to authenticate a transaction. Thetransaction may be used to authenticate the veracity of the point ofsale terminal. The transaction may be used to authenticate a payment tocomplete the purchase.

The foregoing and additional aspects and embodiments of the presentdisclosure will be apparent to those of ordinary skill in the art inview of the detailed description of various embodiments and/or aspects,which is made with reference to the drawings, a brief description ofwhich is provided next.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other advantages of the disclosure will becomeapparent upon reading the following detailed description and uponreference to the drawings.

FIG. 1 shows a randomized PIN layout display on a first device andanother keypad without the digits shown on a second device.

FIG. 2 illustrates the sequence of positions pressed on the seconddevice grid to enter the PIN sequence “1243” using the randomized PINkeypad in the first device.

FIG. 3 illustrates the entry of a PIN in a system with a first, second,and third device where the first and third device have a shared secret.

FIG. 4 illustrates the entry of a PIN in a system with a first, second,third and fourth device where the third and fourth device have a sharedsecret.

FIG. 5 illustrates the entry of a PIN in a system with a first, second,third and fourth device where the fourth device generates the PIN padlayout for the first and third devices.

FIG. 6 illustrates the entry of a PIN in a system with a first, second,and third device where the third device generates the PIN pad layout forthe first device.

FIG. 7 illustrates the entry of a PIN in a system with a first, second,and third device where the first device generates the PIN pad layout forthe third device.

FIG. 8 illustrates the process where the system is initialized.

FIG. 9 illustrates the process where the system is used to process apayment transaction.

While the present disclosure is susceptible to various modifications andalternative forms, specific embodiments or implementations have beenshown by way of example in the drawings and will be described in detailherein. It should be understood, however, that the disclosure is notintended to be limited to the particular forms disclosed. Rather, thedisclosure is to cover all modifications, equivalents, and alternativesfalling within the spirit and scope of an invention as defined by theappended claims.

DETAILED DESCRIPTION

In an exemplary embodiment of the invention comprises a system and amethod to display a randomized PIN layout on a first device and acceptsinput, the PIN token, from the card holder or account holder on a seconddevice in a way that the PIN layout and PIN token never exist on thesame device. Embodiments of the invention may be used by a merchantauthenticating their card reader device with a financial serviceprovider or by a customer to approve a financial transaction.

FIG. 1 illustrates the use of a separate PIN layout and a PIN token. Afirst device 100 contains a display 101 that displays a PIN layout 102.The first device may be a dedicated device for displaying PIN layout, ora card reader which can display the PIN layout, or any devices includingmobile device with suitable methods such as a special application todisplay the PIN layout. The first device may belong to the merchant orthe account holder. The second device 200 may be a smart phone or mobiledevice belonging to the merchant or the account holder.

In some embodiments of the invention, the first device 100 and thesecond device 200 may be coupled together by a wired or wirelessconnection and communicate with each other over the connection in orderto synchronize states between devices. For example, if the PIN keypadlayout changed for every key press, then the first device and the seconddevice must be synchronized to ensure the PIN keypad is fixed for eachinput. In other embodiments of the invention, the first device andsecond device are not required to communicate directly with each other.The first device 100 displays a PIN layout 101 on a screen as atraditional numeric entry keypad. The placement of the digits 0-9 102may be fixed but are preferably randomly generated for each transactionor after each key press. The first device 100 may also have a number ofpredefined layouts with one chosen for each transaction. The firstdevice may also generate pseudo-random layouts based on a secret value,or receive a layout from another device in the system. The second device200 displays a grid 201 of blank keys 202, and may also display othernon-numeric characters in order to control the PIN input such as an OKand Cancel button 203. In use, the user observes the PIN layout 102 ofthe first device in able to know which squares 202 on the second deviceto press to enter their PIN. The first device 100 displays the PINlayout and the second device 200 accepts the PIN token. The user maypress the OK button when the PIN input is complete or press the Cancelbutton to abort the PIN input as is conventionally done. In embodimentsof the invention, the PIN layout and the PIN token never exist on thesame device. This separation adds another layer of security to the PINinput process and helps reduce the complexity of the design of both theapplication on the mobile second device 200 and the peripheral firstdevice 100.

FIG. 2 illustrates the step by step process of entering a PIN token onthe second device 200 based on the PIN layout displayed on the firstdevice 100. In this example, the PIN 1234 is entered. In this example,the PIN layout 102 does not shuffle after each key press. However, inother examples PIN layout 102 randomizes the position of the displayeddigits after every key press. It can be seen that the PIN token input onthe second device 200 represents a position, key, or virtual key. Foreach number, character, or symbol in the PIN, it indicates which key waspressed. The PIN layout as displayed on the first device 100 representsthe value of each position, key, or virtual key at that point in time.By combining the PIN layout and PIN token the PIN can be determined.

FIG. 3 illustrated a first embodiment of the invention for securelyreceiving a PIN input. The system comprises a first device 100 forgenerating and displaying the PIN layout, a second device 200 forcapturing the PIN token 302 from a user, and a third device 300 forreceiving the PIN token and reconstructing the PIN 303 required toauthenticate the transaction.

The first device 100 may be associated with a merchant, bank, orfinancial institution or the card holder, and may be card reader, cashregister, self-checkout counter, or mobile device such as a smart phone,or a dedicated device for such purpose. If the first device is a smartphone device it will run a payment application that may be supplied bythe smart phone manufacturer, a financial institution, a financial cardcompany, or another third party. The first device may also havededicated hardware or software to support encryption and decryption ofsensitive data such as PIN layout mapping 101. The first device may alsohave a dongle or card reading interface that allows it to read secure ornon-secure data from a card. The first device generates a PIN layoutthat may be randomized or may include a finite number of layouts that itchooses from. A new PIN layout 101 is commonly generated for each newtransaction. The first device has a display on which it displays the PINlayout for the transaction. The first device may include wired orwireless communication interfaces in order to communicate with thesecond or a third device 300. The first device stores a shared secret301 that is also stored by the third device. It uses this shared secretas a seed to generate the PIN layout 101. The shared secret need not beshared during transactions. It can be defined during initial setup ofthe devices, or be exchanged periodically. It may be manually input andmay also be loaded or hard coded into devices during manufacture.

The second device 200 may also associated with a merchant, bank, orfinancial institution involved with a financial transaction. It iscommonly a mobile or handheld electronic device such as a smartphone ortablet with an LCD display that accepts touch input, or a point of sale(POS) terminal, or computer system with a display and a hardware toaccepts the PIN input. The second device runs a payment application thatmay be supplied by the smartphone manufacturer, a financial institution,a financial card company, or another third party. The second device mayalso have dedicated hardware or software to support encryption anddecryption of sensitive data such as PIN Token 302. The second devicemay also have a dongle that allows it to read data from a card. Thesecond device displays a keypad 201 that the user may input their PINnumber on. The keypad 201 may be blank, have unmarked rectangles,contain an image, contain a false keypad, or any other display thatallows the user to press buttons 202 or areas on the screen. The userrefers to the PIN display 101 on the first device to determine where topress the keys, buttons, or screen 201 of the second device to inputtheir PIN. The key presses are used to generate the PIN token 302 whichindicates which keys or which areas of the screen 201 were pressed. Thesecond device also includes wired or wireless communication interfacesin order to communicate with the third device. The second device sendsthe PIN Token, in either plaintext or cryptographically protected form,to the third device 300 without passing through the first device 100. Aswell, the randomized PIN layout 101 never exists in second device 200and is never transferred to or through the second device, in any form,plaintext or encrypted. Therefore, the randomized PIN layout 101 and thePIN token 302 only exist in two separate devices, without being presentin the other device. Compromising either one of the device does notcompromise the privacy of the PIN.

The third device 300 is a secure device or a device in a securelocation, for example, a backend server that is located in a securelocation or off site. The third device 300 may be a dedicated device ora computer server running a payment application that may be supplied bythe smartphone manufacturer, a financial institution, a financial cardcompany, or another third party. The third device 300 stores the sameshared secret 301 as the first device 100 and uses it as a seed togenerate the same PIN layout 101 as the first device. In this way, thePIN layout 101 is never transmitted between devices. The third devicereceives the PIN token 302 from the second device 200 and combines itwith the PIN layout 101, that it generates using the shared secret 301,to obtain the PIN 303. The PIN is obtained by using the PIN token todetermine which key was pressed based on the position, key, or virtualkey encoded in the PIN token. This is matched to the PIN layout todetermine the value for the key. This is repeated for each digit orcharacter in the PIN 303. The PIN 303 may then be encrypted. The PIN orthe encrypted PIN is then used to authenticate the transaction.

In some embodiments of the invention, the first device 100 may be thecardholder's device and the second device 200 may be the merchant'ssmart phone, terminal, or device. In this case the PIN layout 101 isdisplayed on the cardholder's device 100 and the PIN token 302 is inputto the merchant's device 200. In other embodiments of the invention, thefirst device 100 may be the merchant's device and the second device 200may be the card holder or account holder's device. In furtherembodiments of the invention, both the first device 100 and the seconddevice 200 are the card holder's devices. In other embodiments of theinvention both the first device 100 and the second device 200 are ownedby the merchant. These embodiments replace present day payment systemswhere the PIN will exist or be stored within a terminal that combinesfunctionality of both the first and second devices.

In embodiments of the invention, the first device 100 that displays thePIN layout, and the second device 200 where the PIN is input must be inproximity to each other so that the person inputting the PIN maymanipulate the second device while viewing the first device. There areno restrictions on the location of the third device 300 and a fourthdevice 400. Either or both of them may be located in the same locationas the first and second device, in a separate room, or in a remotelocation.

FIG. 4 illustrated a second embodiment of the invention for securelyreceiving a PIN input. In this embodiment, the first device 100 has asimplified function to display the PIN layout 101 that it received overa communications interface from a fourth device 400. The randomized PINlayout 101 is generated on by the fourth device 400 using the sharedsecret 301 that it has in common with the third device 300. This allowsthe third and fourth devices to generate or derive the samepseudo-random keypad layout 101 without transmitting the PIN layoutbetween them. The second device is the same as the one mentioned in thefirst embodiment. As before, the PIN token from the second device neverpasses through the first device, in plaintext or encrypted form.

FIG. 5 illustrated a third embodiment the invention for securelyreceiving a PIN input. This embodiment is similar to the secondembodiment as shown in FIG. 4 however, there is no shared secret 301associated with generating the PIN layout 101 shared between the thirddevice 300 and the fourth device 400. Instead the fourth device isresponsible for the generation of the randomized PIN layout 101 andgenerates it on its own. It then transmits the PIN layout to the thirddevice 300 over a wired or wireless communications interface. The PINlayout may be encrypted before transmission by the fourth device. Thethird device receives the encrypted PIN pad layout from the fourthdevice and decrypts it. It also receives the PIN token 302 from thesecond device and uses them to construct the PIN 303.

FIG. 6 illustrated a fourth embodiment of the invention for securelyreceiving a PIN input. This embodiment is a variation on the firstembodiment as shown in FIG. 3. In this embodiment, the first device 100and third device 300 do not have a shared secret. Instead, the thirddevice is responsible for the generation of the randomized PIN layout101 and generates it independently. It then transmits the PIN layout tothe first device 100 over a wired or wireless communications interface.The PIN layout may be encrypted before transmission by the third device300. The first device receives the encrypted PIN pad layout 101 from thethird device and decrypts it.

FIG. 7 illustrated a fifth embodiment of the invention for securelyreceiving a PIN input. This embodiment is another variation on the firstembodiment as shown in FIG. 3. In this embodiment, the first device 100and third device 300 do not have a shared secret. Instead, the firstdevice is responsible for the generation of the randomized PIN layout101 and generates it independently. It then transmits the PIN layout tothe third device 100 over a wired or wireless communications interface.The PIN layout may be encrypted before transmission by the first device300. The third device receives the encrypted PIN pad layout 101 from thefirst device and decrypts it.

There are many variations possible for embodiments of the inventionwhich are not being listed exhaustively. However, in embodiments of theinvention, the PIN layout 101 is not displayed on the device on whichthe PIN token 302 is input. Furthermore, the PIN layout 101 and the PINtoken 302 are never present together on either the first 100 or thesecond device 200, which are generally the devices used at the locationwhere the transaction happens. Both the PIN layout 101 and the PIN token302 are only present on the third device 300 which is a remote or secureserver or device. In this way, compromising the device displaying thePIN layout or the PIN token alone will not allow an intruder todetermine the PIN 303 for the smart card, or mobile device of the cardholder or account holder.

FIG. 8 illustrates an exemplary process of initializing a systemaccording to an embodiment of the invention. To initialize the system700, devices must have any proprietary software installed, user accountsset up, configuration done, and to be authenticated with a paymentprocessor, financial institution, corporate server, or any otherauthoritative or security device. For embodiments that require a sharedsecret 702, either a secret to derive the PIN layout, or a secret forencryption and decryption of other data, this must be configured. Themerchant will then authenticate 703 their card reader device with apayment processor, financial institution, or a corporate server asrequired to ensure that the device is not compromised and being used ina non-fraudulent manner. The merchant may use embodiments of thisinvention to enter a PIN on their device to generate a separate PINlayout 702 and PIN token 704 on separate devices. The PIN is generatedon the third device 707 and used to enable the card reader or point ofsale terminal to allow it to process financial transactions 708.

In FIG. 9 a transaction is initiated 800 when a customer chooses a setof products or services and wished to pay for it. The merchant willcalculate the price of the products and enters the amount 801 in a cashregister or similar device. The customer indicates that they would liketo pay using electronic payment methods such as bank cards or mobilewallets. The merchant then initiates the generation of the PIN layout onthe first device. The first device uses the shared secret to generateand display the PIN layout on its display 802. The PIN layout will berandomized for each transaction. The customer's physical card, virtualcard or wallets will then be swiped, tapped or inserted 803, and thenthe PIN input process will be initiated on the second device. This willcause a blank keypad to be displayed on the second device together withcontrol keys such as OK, Cancel, and backspace. The customer will thenobserve the display on the first device to know the values of the blankkeys of the keypad on the second device and enter the PIN by pressingthe correct blank keys on the second device 804. The second device willtake the positions of the pressed keys to produce the PIN token 805.Once the PIN has been input the second device will transmit the PINtoken to the third device, optionally encrypting it before transmission.The third device with is a dedicated hardware appliance or a server in asecure or off site location receives the PIN token and decrypts it ifnecessary. The third device also uses the shared secret to generate alocal copy of the PIN layout 806. It then combines the local PIN layoutwith the PIN token to produce the PIN 807. The PIN token supplies thelocation of the presses to indicate which keys were pressed. The PINlayout is used to determine the values of the PIN. The PIN is then usedto authenticate the transaction 808.

While particular implementations and applications of the presentdisclosure have been illustrated and described, it is to be understoodthat the present disclosure is not limited to the specific examples ofelectronic payments and point of sale terminal authentication. Manyother applications involving the secure input of a PIN, or other inputinvolving positional information, the token, and layouts involvingnumbers, characters, symbols, pictures or other similar indicators maybenefit from the improved security embodiments of this inventionprovide.

What is claimed is:
 1. A system for accepting input of a PIN from auser, the system comprising: a first device receiving a randomized PINlayout from a fourth device, the fourth device deriving the randomizedPIN layout, and the first device displaying the randomized PIN layout ona first display of the first device to enable the user to enter a seriesof key presses at a second device; the second device comprising an inputfor accepting the series of key presses from the user to produce a PINtoken, the PIN token indicating each of the series of key presses; and athird device in communication with the second device, the third devicederiving the randomized PIN layout and receiving the PIN token from thesecond device without the PIN token being present on the first device,the third device combining the PIN layout and the PIN token to produce aPIN, and the PIN being used to authenticate a transaction.
 2. The systemof claim 1 wherein the fourth device is in communication with the thirddevice, the fourth device and the third device each storing a sharedsecret, the shared secret used to independently derive the randomizedPIN layout on the fourth device and the third device.
 3. The system ofclaim 1 wherein the third device is located remotely from the first andsecond device.
 4. The system of claim 1 wherein the first device and thesecond device comprise a transaction authentication system, thetransaction being used to authenticate the veracity of a point of saleterminal.
 5. The system of claim 4 wherein the transactionauthentication system is used to accept payments from a customer paymentdevice.
 6. A system for accepting input of a PIN from a user, the systemcomprising: a first device receiving a randomized PIN layout from afourth device, the fourth device deriving the randomized PIN layout, andthe first device displaying the randomized PIN layout on a first displayof the first device to enable the user to enter a series of key pressesat a second device; a second device comprising an input for acceptingthe series of key presses from the user to produce a PIN token, the PINtoken indicating each of the series of key presses; and a third devicein communication with the second device and the fourth device, the thirddevice receiving the randomized PIN layout from the fourth device andreceiving the PIN token from the second device without the PIN tokenbeing present on the first device, the third device combining the PINlayout and the PIN token to produce a PIN, and the PIN being used toauthenticate a transaction.
 7. The system of claim 6 wherein the thirddevice is located remotely from the first and second device.
 8. Thesystem of claim 6 wherein the first device and the second devicecomprise a transaction authentication system, the transaction being usedto authenticate the veracity of a point of sale terminal.
 9. The systemof claim 8 wherein the transaction authentication system is used toaccept payments from a customer payment device.
 10. A system foraccepting input of a PIN from a user, the system comprising: a firstdevice receiving a randomized PIN layout from a third device, the thirddevice deriving the randomized PIN layout, and the first devicedisplaying the randomized PIN layout on a first display of the firstdevice to enable the user to enter a series of key presses at a seconddevice; a second device comprising an input for accepting the series ofkey presses from the user to produce a PIN token, the PIN tokenindicating each of the series of key presses; and the third device incommunication with the second device, the third device receiving the PINtoken from the second device without the PIN token being present on thefirst device, the third device combining the PIN layout and the PINtoken to produce a PIN, and the PIN being used to authenticate atransaction.
 11. The system of claim 10 wherein the third device islocated remotely from the first and second device.
 12. The system ofclaim 10 wherein the first device and the second device comprise atransaction authentication system, the transaction being used toauthenticate the veracity of a point of sale terminal.
 13. The system ofclaim 12 wherein the transaction authentication system is used to acceptpayments from a customer payment device.
 14. A method for authenticatinga purchase on a point of sale terminal, the method comprising:displaying a randomized PIN layout on a first device, the first devicereceiving the randomized PIN layout from a fourth device, the fourthdevice deriving the randomized PIN layout, the first device displayingthe randomized PIN layout on a first display of the first device toenable a user to enter a series of key presses at a second device;accepting, at an input of the second device, the series of key presses;producing, by the second device, a PIN token based on said acceptedseries of key presses, the PIN token indicating each of the series ofkey presses; and receiving the PIN token from the second device at athird device without the PIN token being present on the first device,the third device deriving the randomized PIN layout, the third devicecombining the PIN layout and the PIN token to produce a PIN, and the PINbeing used to authenticate a transaction.
 15. The method of claim 14wherein the transaction is used to authenticate the veracity of thepoint of sale terminal.
 16. The method of claim 14 wherein thetransaction is used to authenticate a payment to complete the purchase.17. The method of claim 14 wherein the third device and the fourthdevice derive the randomized PIN layout using a common shared secret.